Space exploration: the unexpected solution to Earth's political, economic, and ecological crises. Dive into the 'Space Expansion Era' for more!
"But by the mid-21st century due to the demographic transition - most countries on Earth will face a population decline. Expansion across the Solar system can potentially get demographic growth back on track; since immigration alone can’t drive the population growth of the colonies to occupy the vast empty spaces of the new worlds."
I don't see how people leaving Earth will help the local population problem. Also, while I agree with the need to explore space, I don't think anything we do in space will fundamentally alter the trajectory of Earth's fertility rates. There are deep structural causes for lower fertility, including high housing, healthcare, education, and childcare costs that are deterring many from having children.